Calibration target for ultrasonic removal of ectoparasites from fish

ABSTRACT

Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for a calibration target for ultrasonic removal of ectoparasites from fish. In some implementations, the calibration target includes a fish-shaped structure, sensors positioned at different locations of the fish-shaped structure, a processor that receives sensor values from the sensors, and a transmitter that outputs sensor data from the calibration target based on the sensor values.

TECHNICAL FIELD

This specification relates to ultrasonic devices that are used in thecontext of aquaculture.

BACKGROUND

Sea lice and other ectoparasites can create significant problems forfarmed fish. When sea lice attach themselves to fish, they feed onfish's natural mucus, which causes lesions to form. Such lesions mayreduce the marketability of farmed fish, and can even cause farmed fishto die. Moreover, if sea lice are too plentiful on a farm, it can causethe farm to be required to shut down because of the effects on wildpopulations.

Sea lice may be extremely difficult to remove, as the sea lice are onlya few millimeters long and may suction themselves very strongly onto theskin of fish. Removal can be even more difficult when sea lice embedthemselves within the mucus of host fish or between fish scales.

SUMMARY

In general, innovative aspects of the subject matter described in thisspecification relate to a calibration target used for the ultrasonicremoval of ectoparasites such as sea lice from fish. Sea lice may beremoved or loosened from fish using ultrasonic signals. For example,ultrasonic signals may be used to generate cavitation bubbles that formunder and around sea lice, allowing water rushing past the fish andnatural motion of fish to dislodge the lice. Ultrasonic signals, evenwithout cavitation bubbles, may also traverse along sea lice to sweepthe sea lice off fish. Additionally, ultrasonic signals may break acarapace of sea lice so that freshwater or another substance lethal onlyto the lice may penetrate and kill the sea lice, or damage/disablereproductive capability.

However, because ultrasonic signals could potentially damage or descalefish, the enhanced techniques described by this specification mayspecifically focus energy on sea lice instead of fish. Because targetingof ultrasonic signals may be difficult, as ultrasonic signals propagatedifferently in water based on many factors such as water temperature,water pressure, water chemistry, concentration of fish mucus, andconcentration of excrement, repeated self-calibration by the device mayenable more accurate targeting. For example, temperature changes alonemay cause ultrasonic signals to converge at locations that arecentimeters apart and a sea lice may only be millimeters long, sorepeated self-calibration may allow the device to determine differentultrasonic signals that converge at a particular location that may bemost effective for louse elimination as temperatures change.

To account for changes in propagation, a sea lice treatment station mayuse self-calibrating ultrasonic removal of sea lice. The sea licetreatment station may include many ultrasonic transducers that aredistributed throughout the sea lice treatment station. The sea licetreatment station may continually perform self-calibration to determinepropagation parameters that take into account how ultrasonic signalspropagate through water within the sea lice treatment station at themoment of treatment. When the sea lice treatment station detects a sealouse on a fish, the sea lice treatment may use the propagationparameters to generate ultrasonic signals that focus energy at or nearthe sea louse. Accordingly, the sea lice treatment station may useultrasonic signals to safely remove sea lice from fish.

A sea lice treatment station may calibrate with a physical calibrationtarget that mimics a fish. The calibration target may have similarphysical properties to fish, and include various sensors distributed onor within the calibration target. Use of the calibration target mayallow accurate prediction of energy that will be present at variouslocations of fish. For example, a sensor of the calibration target maysense exactly how much energy will be present at a specific locationwhere a sensor is positioned after ultrasonic waves reflect off otherportions of the calibration target to the location and other ultrasonicwaves propagate through the fish to that location.

The calibration target may be embedded with sensors at various locationsto measure intensity and rates of phonon propagation. Sensor data fromthe sensors may be used for closed-loop feedback that increases efficacyof beam-forming ultrasonic waves and reduces probability of damage tosensitive regions of fish. The known locations of sensors may also beused to reduce three dimensional (3D) displacement errors and increaseaccuracy and precision of target finding.

One innovative aspect of the subject matter described in thisspecification is embodied in a calibration target that includes afish-shaped structure, sensors positioned at different locations of thefish-shaped structure, where each of the sensors sense energy at arespective location of the fish-shaped structure, a processor thatreceives sensor values from the sensors, and a transmitter that outputssensor data from the calibration target based on the sensor values.

A second innovative aspect of the subject matter described in thisspecification is embodied in a method that includes obtaining initialparameters for ultrasonic transducers around a calibration target, wherethe calibration target includes, a fish-shaped structure, sensors placedat different locations of the fish-shaped structure, where each of thesensors sense energy at a respective location of the fish-shapedstructure, a processor that receives sensor values from the sensors, anda transmitter that outputs sensor data from the calibration target basedon the sensor values, obtaining the sensor data from the calibrationtarget, determining the respective locations of the sensors, anddetermining adjusted parameters for the ultrasonic transducers aroundthe calibration target based on the sensor data and the respectivelocations of the sensors.

A third innovative aspect of the subject matter described in thisspecification is embodied in a calibration target obtained by a processthat includes obtaining a fish-shaped structure, placing sensors atdifferent locations of the fish-shaped structure, where each of thesensors sense energy at a respective location of the fish-shapedstructure, installing a processor that receives sensor values from thesensors, and installing a transmitter that outputs sensor data from thecalibration target based on the sensor values.

Other implementations of this and other aspects include correspondingsystems, apparatus, and computer programs, may be configured to performthe actions of the methods, encoded on computer storage devices. Asystem of one or more computers can be so configured by virtue ofsoftware, firmware, hardware, or a combination of them installed on thesystem that in operation cause the system to perform the actions. One ormore computer programs can be so configured by virtue of havinginstructions that, when executed by data processing apparatus, cause theapparatus to perform the actions.

The foregoing and other embodiments can each optionally include one ormore of the following features, alone or in combination. For instance,in some aspects the fish-shaped structure includes a gill plate portion,a dorsal fin portion, and a caudal fin portion, and the sensors includea first sensor at the gill plate portion, a second sensor at the dorsalfin portion, and a third sensor at the caudal fin portion. In someimplementations, the fish-shaped structure includes a bulk mass thatmimics fish muscle response to the energy, a scale layer that mimicsfish scale response to the energy, where the scale layer is over thebulk mass, and a fish mucus layer that mimics fish mucus response to theenergy, where the fish mucus layer is over the scale layer.

In certain aspects, the sensors include a particular sensor inside aparasite target that mimics parasite response in respect to the energy,where the parasite target is positioned beneath the fish mucus layer andabove the bulk mass. In some aspects, the sensors include ultrasonicsensors that sense ultrasonic energy. In some implementations, thesensor values indicate an amount of ultrasonic energy sensed at therespective locations. In certain aspects, sensors include at least oneof force sensors that sense physical force or photodiodes that senselight.

In some aspects, the processor is a microcontroller that is embeddedwithin the fish-shaped structure, where the microcontroller is coupledto the sensors by electrically conductive wires. In someimplementations, the transmitter outputs the sensor data over anelectrically conductive wire. In certain aspects, the transmitteroutputs the sensor data wirelessly. In some aspects, the sensor dataindicates the respective locations of the sensors positioned at thedifferent locations of the fish-shaped structure. In someimplementations, the fish-shaped structure includes a non-transitorycomputer-readable medium that stores a configuration file that indicatesthe respective locations of the sensors positioned at the differentlocations of the fish-shaped structure.

In certain aspects, determining the respective locations of the sensorsincludes determining parts of the fish-shaped structure that each of thesensors are located at. In some aspects, determining the respectivelocations of the sensors includes determining a location of thecalibration target within a sea lice treatment station. In someimplementations, obtaining the sensor data from the calibration targetincludes determining a first portion of the sensor data from thecalibration target while the calibration target is at a first locationwithin a sea lice treatment station and determining a second portion ofthe sensor data from the calibration target while the calibration targetis at a second, different location within the sea lice treatmentstation.

In certain aspects, obtaining the fish-shaped structure includesobtaining a bulk mass that mimics fish muscle properties in respect tothe energy, forming, over the bulk mass, a scale layer that mimics fishscale properties in respect to the energy, and forming, over the scalelayer, a fish mucus layer that mimics fish mucus properties in respectto the energy. In some aspects, placing sensors at different locationsof the fish-shaped structure includes embedding a particular sensorunderneath the fish mucus layer and inside the scale layer. In someimplementations, the process includes coupling the processor with thesensors by electrically conductive wires.

The above-noted aspects and implementations further described in thisspecification may offer several advantages. For example, the device mayremove sea lice off fish with less damage to the fish than existing sealice removal solutions. In another example, the device may reduce anamount of energy used by more efficiently directing ultrasonic energy atsea lice. In yet another example, the device may increase the health offish being raised in aquaculture environments. In still another example,the device may work in a larger range of environmental conditions (e.g.,temperatures, water chemistries, station geometries, etc.).

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will become apparent from the description,the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing an example of a sea lice treatment system.

FIGS. 2A and 2B are diagrams showing an example sea lice treatmentstation.

FIG. 3 is a diagram showing an example of a sea lice treatment system.

FIG. 4 is a flow diagram illustrating an example of a process forself-calibrating ultrasonic removal of sea lice.

FIG. 5 is a diagram showing a sensitive area around an eye and gills offish.

FIG. 6 is a diagram showing an example of a calibration target.

FIG. 7 is a diagram showing parts of a fish.

FIG. 8 is a diagram of an example system with a calibration target in asea lice treatment station.

FIG. 9 is a flow diagram illustrating an example of a process forcalibrating a sea lice treatment station with a calibration target.

FIG. 10 is a flow diagram illustrating an example of a process formanufacturing a calibration target.

Like reference numbers and designations in the various drawings indicatelike elements. The components shown here, their connections andrelationships, and their functions, are meant to be exemplary only, andare not meant to limit the implementations described and/or claimed inthis document.

DETAILED DESCRIPTION

The subject matter described in this specification describes variousaspects, including a sea lice treatment station in FIGS. 1-5 , and acalibration target in FIGS. 6-10 .

FIG. 1 is a diagram showing an example of a sea lice treatment system100. While the sea lice treatment system 100 is described in variousexamples as treating sea lice, the sea lice treatment system 100 maysimilarly be used to treat other ectoparasites that attach to fish, asdescribed further below. The system 100 includes a fish tank 101 and asea lice treatment station 102 connected to the fish tank 101. A waterpump 103 helps circulate the water of the fish tank 101.

A dotted outline of the first fish 109 is used to illustrate that thefirst fish 109 is inside the sea lice treatment station 102. Analternative view of the sea lice treatment station 102 and the fishbeing treated for sea lice is presented in FIGS. 2A and 2B. A secondfish 110 and a third fish 111 (and perhaps other fish) swim within thefish tank 101. The fish 109 may be placed in the fish tank 101, and maybe observed, by a worker 115.

A visual cutout 104 d is used to show internal elements of the sea licetreatment station 102. The sea lice treatment station 102 includes acamera 104 and ultrasonic transducers 106 a, 106 b (collectivelyreferred to as 106). While only two ultrasonic transducers 106 are shownin FIG. 1 , the sea lice treatment station 102 may include one hundred,two hundred, or some other number of ultrasonic transducers 106.

The ultrasonic transducers 106 may generate ultrasonic signals anddetect ultrasonic signals. For example, the ultrasonic transducers 106may be ultrasonic transceivers, or a combination of ultrasonictransmitters that emit ultrasonic signals and ultrasonic receivers thatsense ultrasonic signals. The camera 104 is shown between the ultrasonictransducers 106. However, the camera 104 may be before the ultrasonictransducers 106 in the direction of water flow, or after ultrasonictransducers 106. While only a single camera is shown, the sea licetreatment station 102 may include multiple cameras to detect sea lice,and may also include lights.

A control unit 112 of the system 100 interfaces with elements includingthe sea lice treatment station 102. The control unit 112 may includedigital electronic circuitry that forms an ultrasonic calibrator, a sealice detector, and a sea lice treatment controller. The ultrasoniccalibrator may determine propagation parameters of the sea licetreatment station 102. For example, the ultrasonic calibrator mayperform self-calibration for a period of five minutes every hour, once aday at a particular time, or some other frequency. Additionally oralternatively, the sea lice treatment station 102 may perform theself-calibration whenever no fish are inside the sea lice treatmentstation 102. For example, the sea lice treatment station 102 maycontinue to perform self-calibration until a fish is detected about toenter the sea lice treatment station 102 by object detection on an imagefrom the camera 104, pause self-calibration while the fish is inside thesea lice treatment station 102, and resume self-calibration once the sealice treatment station 102 detects that the fish has exited the sea licetreatment station 102.

Propagation parameters may reflect how ultrasonic signals propagatethrough water within the sea lice treatment station 102. For example,propagation parameters may specify at least one of: pulse width ofultrasonic signals sensed by the ultrasonic transducers 106, timeoffsets between when ultrasonic signals were generated and sensed by theultrasonic transducers 106, reflections of ultrasonic signals within thesea lice treatment station 102, spectral width of ultrasonic signalssensed by the ultrasonic transducers 106, or phase offset.

The sea lice detector may obtain images from the camera 104 and detectsea lice on fish. For example, the sea lice detector may detect a sealouse on one side of a tail of the fish 109. The sea lice treatmentcontroller may, based on the propagation parameters, generate ultrasonicsignals that focus energy on the sea louse that was detected. Forexample, the sea lice treatment controllers may determine differentultrasonic signals to be generated by different ones of the ultrasonictransducers 106, where energy of the signals converges so the locationwith highest energy is at the sea louse.

Stages A-C of FIG. 1 depict an example of the operation of the system100. Specifically, in stage A, before the fish 109 enters to sea licetreatment station 102, the ultrasonic calibrator generates and sensesultrasonic signals by the ultrasonic transducers 106 and determinespropagation parameters from the ultrasonic signals sensed. The sensedultrasonic signals may be directly transmitted signals or reflectedsignals.

In stage B, the first fish 109 swims into the sea lice treatment station102. When the fish 109 is within the field of view of the camera 104,the sea lice detector may receive images of the fish 109 and use objectrecognition to detect sea lice on the fish 109. For example, the sealice detector may detect a sea louse on a tail of the fish by performingimage-based object recognition on one or more images from the camera104.

In stage C, the sea lice treatment controller may determine a set ofultrasonic signals that, when generated by the ultrasonic transducers106, focuses energy on the location of the sea louse within the sea licetreatment station 102. For example, the sea lice treatment controllermay determine to only generate ultrasonic signals on thirty of twohundred ultrasonic transducers 106, where the ultrasonic signals aredifferent from one another and converge most energy at the location ofthe sea louse.

In some implementations, stages B and C may repeat until all sea liceare removed or loosened from the fish 109. For example, stages B and Cmay repeat once every one fifty milliseconds while the fish 109 iswithin the sea lice treatment station 102. In another example, stages Band C may be performed once each time the fish 109 passes through thesea lice treatment station 102. In some implementations, the energyfocused on the sea louse may be increased until the sea lice detector nolonger detects the sea louse on the fish or a maximum energy limit thatis safe for fish is reached.

After sea lice treatment in the sea lice treatment station 102 takesplace, the first fish 109 may exit the sea lice treatment station 102and resume swimming freely within the fish tank 101. Further detectionsby the system 100 can take place concerning the second fish 110 afterthe second fish 110 swims around the fish tank 101 and into the sea licetreatment station 102. Once the second fish 110 is within the sea licetreatment station 102, the sea lice treatment station 102 can treat thesecond fish 110 for sea lice in a similar manner to discussed above inreference to the first fish 109.

In some implementations, the sea lice treatment system 100 may notinclude a camera. The sea lice treatment system 100 might be so gentlethat ultrasonic signals may provide ultrasonic energy all over the fish,or the sea lice treatment system 100 might always target behind theadipose and dorsal fins where lice is most commonly found. For example,the sea lice treatment system 100 may detect the presence, location,size, and orientation of fish based on changes in ultrasonic signalssensed by the ultrasonic transducers 106 and then, without attempting todetect sea lice on the fish, transmit ultrasonic signals with theultrasonic transducers 106 according to the propagation parameters thattarget a predetermined amount of ultrasonic energy at the adipose anddorsal fins.

FIGS. 2A and 2B are diagrams showing an example sea lice treatmentstation. FIG. 2A shows a side view of the sea lice treatment station 102and FIG. 2B shows a cross-sectional view of the sea lice treatmentstation 102. A shown in FIG. 2A, the sea lice treatment station 102 mayinclude ultrasonic transducers 106 a-106 h distributed along the top andbottom of the sea lice treatment station 102. FIG. 2B shows that theultrasonic transducers 106 b, 106 f, and 106 i-106 p may be distributedalong four walls of the sea lice treatment station 102. However, the sealice treatment station 102 may have other geometries. For example, thesea lice treatment station may be cylindrical with ultrasonictransducers distributed along a single inner wall or shaped as anoctogon with ultrasonic transducers distributed along eight walls. Insome implementations, the sea lice treatment station may have a geometrythat is designed to have oppositely curved wall sections to act as afocusing/resonant cavity or, in contrast, have lightly changed angles ofplanar surfaces to reduce back reflection directly into a localtransducer.

For example, for a sea louse located on the left of the fish as shown inFIG. 2B, the sea lice treatment controller may receive x, y, zcoordinates of the sea louse in the sea lice treatment station 102 fromthe sea lice detector, determine a position of the fish 109 based onimages from the camera 104, and determine a particular combination ofultrasonic signals to be generated by only ultrasonic transducers 106 b,106 f, and 106 k.

The sea lice treatment controller may determine the ultrasonic signalsto generate based on obtaining stored propagation parameters for each ofthe ultrasonic transducers 106 a-106 p and calculating a combination ofultrasonic signals to be generated by the ultrasonic transducers thatincreases ultrasonic energy at the location of the sea louse relative toother locations in the sea lice treatment station 102, especially wherethe fish is located.

For example, the sea lice treatment controller may determine to generateparticular ultrasonic signals at only ultrasonic transducers 106 b, 106f, and 106 k. The determination may be based on determining thataccording to the propagation parameters for all of the ultrasonictransducers 106 a-106 p that the combination of the particularultrasonic signals are expected to propagate to focus more energy at thesea louse, while maintaining a safe amount of energy at the fish, thanany other combination of ultrasonic signals.

As mentioned in FIG. 1 , the propagation parameters for the ultrasonictransducers 106 a-106 p may be determined during a periodic calibrationbefore the fish 109 enters the sea lice treatment station 102. Forexample, the ultrasonic calibrator may, for each of the ultrasonictransducers 106 a-106 p, iteratively generate ultrasonic signals atdifferent frequencies, pulse duration, signal duration, amplitudes,phase delay, and phase launch, and detect the ultrasonic signals at theother transducers to determine propagation parameters for the ultrasonictransducer that transmitted the ultrasonic signals. The determination ofpropagation parameters and calculation of ultrasonic signals based onthe propagation parameters is discussed in more detail below in regardsin FIG. 4 .

While FIG. 2A only shows two ultrasonic transducers transmitting andFIG. 2B only shows three ultrasonic transducers transmitting, in someother examples, five, ten, fifteen, fifty, one hundred, three hundred,or some other number of hundreds of transducers may simultaneouslytransmit ultrasonic signals.

FIG. 3 is a diagram showing an example of a sea lice treatment system300. The system 300 is shown in an open water environment. Nets 301 and302 are used in this implementation to direct fish into a sea licetreatment station 304. The system 300 includes the nets 301 and 302, thesea lice treatment station 304, a fish 311 (shown in three stages as 311a, 311 b and 311 c), a tube 312 feeding into the sea lice treatmentstation 304, and a weight 314 that provides stability to the sea licetreatment station 304.

The sea lice treatment station 304 is another implementation of the sealice treatment station 102 shown in FIG. 1 and FIGS. 2A and 2B. The sealice treatment station 304 similarly includes a camera and ultrasonictransducers.

FIG. 3 is shown in three stages. Stage A corresponds to the fish 311 aentering the tube 312. Stage B corresponds to the fish 311 b within thesea lice treatment station 304 being treated for sea lice. Stage Ccorresponds to the fish 311 c exiting the sea lice treatment station 102through the tube 312.

Stage A of FIG. 3 shows the fish 311 a entering the tube 312 from thenet 301 enclosure. Other fish are within the net 301. In general, thereis no limit to the number of fish able to be processed by the sea licetreatment station 304.

Stage B of FIG. 3 shows the fish 311 b within the sea lice treatmentstation 304 being treated for sea lice. The fish 311 b is arepresentation of the fish 311 a shown at a later time in a differentlocation. The sea lice treatment station 304 uses a control unit similarto the control unit 112 of FIG. 1 to calibrate ultrasonic signals,detect sea lice, and treat for sea lice.

Stage C of FIG. 3 shows the fish 311 c exiting the sea lice treatmentstation 102 through the tube 312. An incentive can be used to move thefish from the tube 312 to the net 302. Depending on implementation, theincentive can include food or physical forces such as water currents.

In some implementations, the sea lice treatment system 300 can befloating within a body of water. For example, the sea lice treatmentsystem 300 can be submerged within a body of water containing one ormore fish. The one or more fish contained within the body of water maybe processed by the sea lice treatment system 300.

FIG. 4 is a flow diagram illustrating an example of a process 400 forself-calibrating ultrasonic removal of sea lice. Briefly, and as will bedescribed in more detail below, the process 400 includes generating, bytransducers distributed in a sea lice treatment station, a first set ofultrasonic signals, detecting a second set of ultrasonic signals inresponse to propagation of the first set of ultrasonic signals throughwater, determining propagation parameters of the sea lice treatmentstation based on the second set of ultrasonic signals that weredetected, obtaining an image of a sea louse on a fish in the sea licetreatment station, determining, from the image, a location of the sealouse in the sea lice treatment station, and generating a third set ofultrasonic signals that focuses energy at the sea louse.

The process 400 includes generating, by transducers distributed in a sealice treatment station, a first set of ultrasonic signals (402). Forexample, the ultrasonic calibrator may control the ultrasonictransducers 106 to generate ultrasonic signals.

The process 400 includes detecting a second set of ultrasonic signals inresponse to propagation of the first set of ultrasonic signals throughwater (404). For example, the ultrasonic calibrator may control theultrasonic transducers 106 to detect for ultrasonic signals.

In some implementations, detecting, by the ultrasonic transducers, asecond set of ultrasonic signals in response to propagation of the firstset of ultrasonic signals through water includes detecting, by a firstultrasonic transducer, ultrasonic signals in response to propagation ofa first ultrasonic signal that was generated by a second ultrasonictransducer and detecting, by the first ultrasonic transducer, ultrasonicsignals in response to propagation of a second ultrasonic signal thatwas generated by a third ultrasonic transducer after the firstultrasonic signal was generated. For example, while calibrating, theultrasonic calibrator may generate an ultrasonic signal with one of theultrasonic transducers 106, detect for the ultrasonic signal at all ofthe ultrasonic transducers 106, and then repeat both steps for each ofthe ultrasonic transducers 106.

In some implementations, instead of generating ultrasonic signalssequentially during calibration as described above, the ultrasoniccalibrator may generate ultrasonic signals in parallel. For example, theultrasonic calibrator may use the standing wave approach and usevariable coded phase shifts to differentiate which signals are comingfrom which transducers without needing to run one at a time. If usingthe pulsed approach, the ultrasonic calibrator may use a similarencoding technique such as pulse width modulation or pulse densitymodulation that differentiates each transmitter so receivers can tellthem apart.

The process 400 includes determining propagation parameters of the sealice treatment station based on the second set of ultrasonic signalsthat were detected (406). For example, the ultrasonic calibrator maydetermine propagation parameters of the sea lice treatment station 102based on what ultrasonic signals were generated at the ultrasonictransducers 106 and resultant ultrasonic signals detected at theultrasonic transducers 106.

In some implementations, determining propagation parameters of the sealice treatment station based on the second set of ultrasonic signalsthat were detected includes determining at least one of pulse width ofultrasonic signals of the second set of ultrasonic signals, time offsetsbetween detections of the second set of ultrasonic signals andgeneration of the first set of ultrasonic signals, spectral width, phaseoffset, or reflections of the first set of ultrasonic signals. Forexample, the ultrasonic calibrator may determine the millisecondsbetween when an ultrasonic signal is generated at a first transducer andthe ultrasonic signal is detected at a second transducer. In someimplementations, determining propagation parameters may includedetermining precise transducer locations.

The process 400 includes obtaining an image of a sea louse on a fish inthe sea lice treatment station (408). For example, the sea lice detectormay receive an image captured by the camera 104, where the image showsthe fish 109 inside the sea lice treatment station 102.

The process 400 includes determining, from the image, a location of thesea louse in the sea lice treatment station (410). For example, the sealice detector may use object recognition to detect a sea louse on a tailof the fish 109, where the sea louse is detected to be in an exactmiddle of the water containing portion of the sea lice treatment station102.

The process 400 includes generating a third set of ultrasonic signalsthat focuses energy at the sea louse (412). For example, the sea licetreatment controller may control the ultrasonic transducers 160 togenerate ultrasonic signals that focus energy at the exact middle of thewater in the sea lice treatment station 102.

In some implementations, generating a third set of ultrasonic signalsthat focuses energy at the sea louse includes determining, from theimage, that a portion of the fish is not between a particular ultrasonictransducer and the sea louse, generating an ultrasonic signal of thethird set of ultrasonic signals with the particular ultrasonictransducer. For example, from the perspective shown in FIG. 2A, the sealice detector may determine that a sea lice is on the left side of thefish 109 which is directly in line of sight of the ultrasonic transducer106 k and, in response, determine to use the ultrasonic transducer 106 kto generate one of the ultrasonic signals in the set of ultrasonicsignals used to remove a sea louse.

In some implementations, generating a third set of ultrasonic signalsthat focuses energy at the sea louse includes determining, from theimage, that a portion of the fish is between a particular ultrasonictransducer and the sea louse and based on determining, from the image,that the portion of the fish is between the particular ultrasonictransducer and the sea louse, determining not to generate an ultrasonicsignal with the particular ultrasonic transducer. For example, theperspective shown in FIG. 2A, the sea lice detector may determine that asea lice is on a left side of the fish 109 which is blocked from line ofsight of the ultrasonic transducer 106 n by the fish 109 and, inresponse, determine not to use the ultrasonic transducer 106 n togenerate any of the ultrasonic signals in the set of ultrasonic signalsused to remove a sea louse.

In some implementations, generating, by the ultrasonic transducers andbased on the propagation parameters and the location of the sea louse inthe sea lice treatment station, a third set of ultrasonic signals thatfocuses energy at the sea louse includes determining phases ofcontinuous wave ultrasonic signals in the third set of ultrasonicsignals. For example, the ultrasonic signals may be continuous waveswhich vary in phase and period.

In some implementations, the process 400 includes generating, by theultrasonic transducers and based on the propagation parameters and thelocation of the sea louse in the sea lice treatment station a third setof ultrasonic signals that focuses energy at the sea louse, includesdetermining time delays of pulsed ultrasonic signals in the third set ofultrasonic signals. For example, the ultrasonic signals may be pulsessent with different time delays.

In some implementations, the process 400 includes obtaining sensor datafrom at least one of a water temperature sensor, a water pressuresensor, or a water salinity sensor, where determining propagationparameters of the sea lice treatment station is based on the sensor dataand the second set of ultrasonic signals that were detected. Forexample, the ultrasonic calibrator may use a current water temperatureof 70° F. sensed by chemical properties of a thermometer to determinepropagation parameters for other temperatures of water.

In some implementations, the process 400 includes determining thatultrasonic signals generated by a particular ultrasonic transducersatisfy self-cleaning criteria, and based on determining that ultrasonicsignals generated by the particular ultrasonic transducer satisfyself-cleaning criteria, generating, by the ultrasonic transducers, afourth set of ultrasonic signals that focus energy at the particularultrasonic transducer. For example, the ultrasonic calibrator maydetermine that ultrasonic signals emitted by a particular transducer aresensed by other transducers as weaker than typical and, in response,determine that dirt, bio-foul, growth, or some other substance on theparticular transducer might be interfering with signals from theparticular transducer so direct energy at the particular transducer toattempt to remove dirt. In another example, the sea lice detector mayvisually determine that a particular transducer looks dirty in an imageand, in response, direct energy at the particular transducer to attemptto remove dirt.

In some implementations, the process 400 includes determining that thesea louse is located near a particular part of a fish and determiningultrasonic signals accordingly. For example, the sea lice treatmentcontroller may determine that the sea louse is within one centimeter ofan eye of a fish or gills and, in response, determine not to generateultrasonic signals to remove the sea louse to protect the sensitive eyeor gills area. FIG. 5 is a diagram 500 showing a sensitive area 510around an eye and gills of fish.

In another example, the sea lice treatment controller may determine thatthe sea louse is on a dorsal fin and, in response, determine to targetthe maximum energy limit that is safe for fish at the sea louse. Forexample, tough skin on the fish's spine may withstand stronger pressuresfrom the ultrasonic transducers than more sensitive portions, near gillsor eyes for example, which may require gentler pressures. In someimplementations, the sea lice treatment controller may determine that anarea of a particular fish is too damaged for the application of energyand, in response, choose not to fire to prevent death or damage to analready wounded fish.

In some implementations, the process 400 includes determining thatanother fish is located between the sea louse and an ultrasonictransducer. For example, the sea lice treatment controller may determinefrom an image captured by the camera 104 that a second fish is betweenthe ultrasonic transducer 106 k and the sea louse on a first fish and,in response, determine to generate a set of ultrasonic signals thatfocuses energy at the sea louse without transmitting from the ultrasonictransducer 106 k as signals from the ultrasonic transducer 106 k areexpected to be blocked by the second fish. In another example, the sealice treatment controller may determine from an image captured by thecamera 104 that no other fish is between the ultrasonic transducer 106 kand the sea louse on a first fish and, in response, determine thatultrasonic signals may be generated by ultrasonic transducer 106 k asultrasonic signals generated by the ultrasonic transducer 106 k are notexpected to be blocked by any other fish.

In some implementations, the process 400 includes determining thatanother fish is located in a particular location and, in response,determining to generate ultrasonic signals that do not generate a sidelobe where ultrasonic energy is focused at the particular location. Forexample, the sea lice treatment controller may determine from an imagecaptured by the camera 104 that a second fish is in a corner of the sealice treatment station 102 and, in response, determine to generateultrasonic signals that keep ultrasonic energy at the corner below anenergy threshold while focusing energy on a sea louse attached to afirst fish.

In some implementations, a second process for self-calibratingultrasonic removal of sea lice may, similarly to process 400, generate afirst set of ultrasonic signals, detect a second set of ultrasonicsignals, and determine propagation parameters. The second process maythen store the propagation parameters for later treatment of sea lice.For example, the sea lice treatment station 102 may perform the secondprocess during stage A, and then store the propagation parameters.

A third process for self-calibrating ultrasonic removal of sea lice may,similarly to process 400, obtain an image of a sea louse and determine alocation of the sea louse. The third process may then access propagationparameters previously stored. For example, the sea lice treatmentstation 102 may receive and store propagation parameters determined fromsome other device, and later access the propagation parameters fromstorage. The third process may continue with similarly generating a setof ultrasonic signals that focuses energy at the sea louse.

In some implementations, a fourth process for self-calibratingultrasonic removal of sea lice may not focus energy at a detected sealouse. For example, similarly to process 400, the fourth process maygenerate a first set of ultrasonic signals, detect a second set ofultrasonic signals, and determine propagation parameters. However,instead of obtaining an image of a sea louse, the fourth process mayinstead detect the presence, location, size, and orientation of fishbased on changes in ultrasonic signals sensed by the ultrasonictransducers 106 and then, without attempting to detect sea lice on thefish, transmit ultrasonic signals with the ultrasonic transducers 106according to the propagation parameters that target a predeterminedamount of ultrasonic energy at the adipose and dorsal fins.

In some implementations, the detection of sea lice can include specificspecies or stages of sea lice. For example, the several species of sealice may include ectoparasitic copepods of the genera Lepeophtheirus andCaligus. The type of fish being analyzed can affect the process of sealice detection. For example, upon detection of a salmon, a system canadapt a system of detection for the detection of Lepeophtheirussalmonis—a species of sea lice which can be especially problematic forsalmon. In some implementations, a detection of a specific species ofsea lice can be separated from other sea lice detections. For example,detection of Lepeophtheirus salmonis can be treated separately fromdetections of Caligus curtis and Lepeophtheirus hippoglossi.

While implementations are described above in the context of sea liceremoval on salmon, self-calibrating ultrasonic removal may also be usedto remove sea lice from other fish, or other ectoparasites from fish.For example, the sea lice treatment station 102 may remove sea lice fromsea trout or three-spined stickleback, or remove Benedenia seriolae, anectoparasitic flatworm that suctions onto yellowtail fish. Accordingly,the sea lice treatment system 100 may also be referred to as anectoparasite treatment system, the sea lice detector may also bereferred to as an ectoparasite detector, the sea lice treatmentcontroller may also be referred to as an ectoparasite treatmentcontroller, and references to sea lice and sea louse described above inregards to FIG. 4 and the first through fourth processes may be replacedwith references to ectoparasites other than sea lice or more generallyectoparasites.

FIG. 6 is a diagram showing an example of a calibration target 600. Thecalibration target 600 may mimic a shape of a fish and be used tocalibrate a sea lice treatment station. For example, calibration target600 may be shaped like a salmon and be placed inside the sea licetreatment station 102 while the sea lice treatment station 102 is beingcalibrated. Briefly, and as will be described in more detail below, thecalibration target 600 includes a fish-shaped structure 610, sensors620A-H (collectively referred to as 620), a processor 630, and atransmitter 640. A calibration target 600 may be referred to as aphantom fish as the calibration target 600 may have a known size andknown composition that is similar to an actual fish, and be used formeasuring performance of a sea lice treatment station 102.

The fish-shaped structure 610 may be a physical object that has a shapesimilar to a fish, e.g., salmon, catfish, carp, trout, tilapia, halibut,or bass, etc. FIG. 7 is a diagram showing parts of a fish 700 that is asalmon. The fish 700 includes, as shown in a left lateral side, anostril, an eye, a maxillary bone, a gill plate, a pectoral fin, adorsal fin, a lateral line, a pelvic fin, an anal fin, an adipose fin,and a caudal fin. The fish-shaped structure 610 may include portionsthat correspond to each of the parts described above in the fish 700.For example, the fish-shaped structure 610 may include a gill plateportion near the front of the fish-shaped structure 610 where a gillplate is on the fish 700, a dorsal fin portion in the mid top of thefish-shaped structure 610 where a dorsal fin is on the fish 700, acaudal fin portion at the back end where the caudal fin is on the fish700, etc.

The calibration target 600 may have a geometric shape and surfacetexture of a fish, and material variation throughout to maintain energypropagation that corresponds to an actual fish. For example, thecalibration target 600 may have ultrasonic wave propagation fidelitythat corresponds to an actual fish. Different portions of thecalibration target 600 may be made of different material that propagatesenergy differently. For example, a first portion of the calibrationtarget 600 may be made of a material that has a different acousticimpedance property than a second portion of the calibration target 600.

The fish-shaped structure 610 includes a bulk mass 616, a scale layer618, and a fish mucus layer 612. The bulk mass 616 may mimic fish muscleresponse to energy. For example, the bulk mass 616 may be made of one ormore of silicone or rubber derivatives such as latex or isoprene thathas a similar acoustic impedance property or phonon propagation speedconstants to fish muscle. In some implementations, the bulk mass 616 maybe made of different material at different locations. For example, asthe dorsal fin of fish may include dense muscle and the gill plate offish may include soft gills, the bulk mass 616 around a gill plateportion of the calibration target 600 may be made of a material that hasa different acoustic impedance property than a dorsal fin portion of thecalibration target 600.

The scale layer 618 may be over the bulk mass 616 and mimic fish scaleresponse to energy. For example, the scale layer 618 may be made of athin ceramic coat that surrounds the bulk mass 616 and has a similaracoustic impedance property to fish scales. In some implementations, thescale layer 618 may be formed by a pattern cut into the bulk mass 616.For example, the scale layer 618 may be a top layer of the bulk mass 616that has one millimeter deep cuts that form small triangles on a surfaceof the bulk mass 616. In some implementations, the material of the scalelayer 617 may match a coefficient of thermal expansion of a fish. Forexample, the thin ceramic coat may be made of a material with the samecoefficient of thermal expansion of fish.

The fish mucus layer 612 may mimic fish mucus response to energy. Forexample, the fish mucus layer may be made of a gel or jelly-likesubstance that has a similar acoustic impedance property to fish mucus.

The sensors 620 may be positioned at different locations of thefish-shaped structure 610. For example, the sensors 620 may include afirst sensor 620A located at an eye portion of the fish-shaped structure610, a second sensor 620B located at a gill plate portion of thefish-shaped structure 610, a third sensor 620C located at a dorsal finportion of the fish-shaped structure 610, a fourth sensor 620D locatedat a pectoral fin portion of the fish-shaped structure 610, a fifthsensor 620E located at a pelvic fin portion of the fish-shaped structure610, a sixth sensor 620F located at an anal fin portion of thefish-shaped structure 610, and a seventh sensor 620G located at a caudalfin portion of the fish-shaped structure 610.

In some implementations, the different locations that the sensors 620are positioned at may be optimized for different fish shapes anddifferent calibration techniques. For example, machine learning may beused to determine a set of locations for a limited number of sensors forsalmon.

The sensors 620 may be located above, below, or within the bulk mass616, the scale layer 618, and the fish mucus layer 612. For example, tomeasure energy experienced by an actual fish eye which would be belowfish mucus and not below scales, the first sensor 620A may be located atthe eye portion of the fish-shaped structure 610, below the fish mucuslayer 612, and above the scale layer 618. In another example, to measureenergy experienced by actual fish muscles that would be below scales,the third sensor 620C may be located at the dorsal fin portion of thefish-shaped structure 610, below the scale layer 618, and above the bulkmass 616.

In some implementations, the sensors 620 may include a particular sensorinside a parasite target that mimics parasite response to energy. Forexample, the parasite target may be the size and shape of sea lice, andbe made of a material that has a similar acoustic impedance property asshells of sea lice. The parasite target may be positioned beneath thefish mucus layer 612 and above the bulk mass 616 similarly to how sealice may be between fish scales. For example, the parasite target may beembedded within the scale layer 618 or placed on top of the scale layer618. The particular sensor within the parasite target may measure energythat would be experienced by actual sea lice.

In some implementations, a sensor may not be inside the parasite target,but one or more sensors may be positioned around the parasite target.For example, a first particular sensor may be positioned between theparasite target and the fish mucus layer 612, and a second particularsensor may be positioned between the parasite target and the bulk mass616. Accordingly, the energy that would be experienced by actual sealice may be extrapolated based on the energies sensed by the firstparticular sensor and the second particular sensor.

In some implementations, the sensors may be one or more of ultrasonicreceivers that sense ultrasonic signals, force sensors that sensephysical force, photodiodes that sense light, or microphones that sensesound. For example, the sensors 620 may each include an ultrasonicreceiver, a force sensor, a photodiode, and a microphone.

The processor 630 may receive sensor values from the sensors 620. Forexample, the processor 630 may receive a first value from the firstsensor 620A, a second value from the second sensor 620B, etc. Themagnitude of the sensor values may reflect an amount of energy sensed bythe sensors 620. For example, a sensor value from the first sensor 620Athat is double a sensor value from the second sensor 620B may reflectthat twice as much energy was sensed at the first sensor 620A.

The processor 630 may store sensor values from the sensors 620. Forexample, the processor 630 may store the sensor values on anon-transitory computer readable medium also within the calibrationtarget. In some implementations, the processor 630 may performprocessing on the sensor values and store the processed sensor values assensor data. For example, the processor 630 may receive sensor valuesfrom the first sensor 620A, determine averages of the sensor values forten nanosecond time intervals, label each of the averages with anindication of the time interval and an indication of the first sensor620A, and store the labeled averages as sensor data. In another example,the processor 630 may store the sensor values labeled with an indicationof the first sensor 620A and an indication of the time received as thesensor data.

In some implementations, the sensor data indicates the respectivelocations of the sensors positioned at the different locations of thefish-shaped structure. For example, the sensor data may represent eachsensor value with an indication of a location of a sensor that providedthe sensor value. In another example, the sensor data may represent eachsensor value with an indication of a sensor that provided the sensorvalue, and a server may then determine a location of the sensor based ona configuration file that identifies where each sensor was located.

In some implementations, the fish-shaped structure 610 includes anon-transitory computer-readable medium that stores a configuration filethat indicates the respective locations of the sensors positioned at thedifferent locations of the fish-shaped structure. For example, thefish-shaped structure may include a non-volatile memory card that hasmemory that is accessible to the processor 630 and stores theconfiguration file, and the processor 630 may output the configurationfile to a server separately from the sensor data.

The transmitter 640 outputs sensor data from the calibration targetbased on the sensor values. For example, the transmitter 640 outputssensor data that is generated by the processor 630 from the sensorvalues. In some implementations, the transmitter 640 may transmit thelabeled averages through an electrically conductive wire that is coupledto a server. For example, a waterproof thin wire 632 may extend from thecalibration target 600 through water and connect to a server. In someimplementations, the transmitter 640 may wirelessly transmit the sensordata to a server. For example, the transmitter 640 may transmit thesensor data over Bluetooth, WiFi, or some other wireless technology.

FIG. 8 is a diagram of an example system 800 with a calibration target600 in a sea lice treatment station 102. In the system 800, thecalibration target 600 provides sensor data to the control unit 112 overthe waterproof thin wire 632. For example, the calibration target 600may provide sensor data generated in response to different ultrasonicsignals emitted by the ultrasonic transducers 106. In another example,the calibration target 600 is slowly moved through the sea licetreatment station 102 and sensor data for different ultrasonic signalsemitted by the ultrasonic transducers 106 is obtained at each of thedifferent locations.

The calibration target 600 may be mounted on wires. For example, thecalibration target 600 may be mounted with the wires 812A and 812B(collectively referred to as 812). The wires may be attached to variouslocations of the calibration target 600. For example, the wire 812A maybe attached to a front of the calibration target 600 and the wire 812Bmay be attached to a back of the calibration target 600. The wires mayhave a thickness that is less than a wavelength of the sensed energy andhave a low mass to reduce interference of the energy by the wires. Forexample, the wires may be monofilaments with a thickness less than onemillimeter. In some implementations, the wires may have a triangularcross section that reduces specular back reflection.

In some implementations, the calibration target 600 may be mounted on astick covered with energy anechoic structure instead of mounted onwires. For example, the stick may be a long stick covered withultrasonic anechoic structure and have one end mounted on thecalibration target 600 underwater and another end above water held by aperson. In some implementations, the calibration target 600 may not bemounted to anything, and may instead be neutrally buoyant and floatthrough the sea lice treatment station 102.

FIG. 9 is a flow diagram illustrating an example of a process 900 forcalibrating a sea lice treatment station with a calibration target. Forexample, the sea lice treatment station 102 may be calibrated with thecalibration target 600. The process 900 may be used so that ectoparasiteremoval is gentle enough on fish to remove ectoparasites but strongenough to remove parasites, and may be used in closed loop monitoringand adjusting of energy application by the sea lice treatment station.

The strength needed to remove ectoparasites at different locations offish may be pre-determined in a laboratory environment using real licestuck on fish skins. There may be a high variability on the amount ofenergy necessary to remove a louse from a fish, or to sufficientlydamage a louse such that it is no longer able to maintain vitality inthe short term. The amount of energy may vary not only based on initialperformance of the sea lice treatment station 102, but also on manyapplication specifics such as environmental conditions, fishsize/geometry, fish transit rate, louse size, local water temperatureand chemistry, etc. Determination of the amount of energy may bedetermined with repeated trials that establish higher drive conditionsfor higher efficacy. Direct testing of specific cases for a sufficientlywide baseline of real geometry, fish and louse configurations, or atleast sufficiently large as to be a representative baseline from whichphysical models with known constants (such as phonon propagation speedthrough water as a function of salinity and temperature), can supportextrapolation.

The process 900 includes obtaining initial parameters for ultrasonictransducers around a calibration target (910). For example, the controlunit 112 may obtain initial parameters for the ultrasonic transducersbased on a configuration file that specifies initial parameters to usefor calibration. In another example, the control unit 112 may obtaininitial parameters for the ultrasonic transducers from user input.

The process 900 includes obtaining the sensor data from the calibrationtarget (920). For example, the control unit 112 may receive sensor dataoutput by the transmitter of the calibration target 600 while thecalibration target 600 moves through different portions of the sea licetreatment station 102.

In some implementations, obtaining the sensor data from the calibrationtarget includes determining a first portion of the sensor data from thecalibration target while the calibration target is at a first locationwithin a sea lice treatment station and determining a second portion ofthe sensor data from the calibration target while the calibration targetis at a second, different location within the sea lice treatmentstation. For example, the first portion of the sensor data may bedetermined by the control unit 112 while the calibration target 600 isin the exact middle of a portion of the fish tank 101 within the sealice treatment station 102, and the second portion of the sensor datamay be determined by the control unit 112 while the calibration target600 is at a bottom back farthest corner of the portion of the fish tank101 within the sea lice treatment station 102.

The process 900 includes determining the respective locations of thesensors (930). For example, the control unit 112 may determine that thefirst sensor 620A is located at the eye region. In some implementations,determining the respective locations of the sensors includes determiningparts of the fish-shaped structure that each of the sensors are locatedat. For example, the control unit 112 may determine which part of thefish-shaped structure 610 each of the sensors 620 is located at. In someimplementations, the control unit 112 may determine parts of thefish-shaped structure that each of the sensors is located at based on aconfiguration file that specifies where each of the sensors 620 islocated. For example, the control unit 112 may receive a configurationfile from the calibration target 600 or the control unit 112 maygenerate and store a configuration file based on user input thatspecifies where each sensor is located.

In some implementations, determining the respective locations of thesensors includes determining a location of the calibration target withina sea lice treatment station. For example, the control unit 112 maydetermine that the calibration target 600 is in the exact middle of aportion of the fish tank 101 within the sea lice treatment station 102,and determine the location of the sensor based on the location of thecalibration target 600 being in the exact middle. In another example,the control unit 112 may determine that the calibration target 600 is ata bottom back farthest corner of the portion of the fish tank 101 withinthe sea lice treatment station 102. In some implementations, determininga location of the calibration target within a sea lice treatment stationincludes determining the location of the calibration target within thesea lice treatment station with a secondary localization system. Forexample, the sea lice treatment station 102 may determine that thecalibration target 600 is in the exact middle of the portion of the fishtank 101 within the sea lice treatment station 102 based on visuallyrecognizing the calibration target 600 in video from cameras.

The process 900 includes determining adjusted parameters for theultrasonic transducers around the calibration target based on the sensordata and the respective locations of the sensors (940). For example, thecontrol unit 112 may determine adjusted parameters that reduceultrasonic energy at a location that the sensor data indicates isreceiving too much ultrasonic energy. In another example, the controlunit 112 may determine adjusted parameters that increase ultrasonicenergy at a location that the sensor data indicates is receiving toolittle ultrasonic energy.

In some implementations, the process 900 may be performed by acalibration target instead of the control unit 112. For example, theprocess 900 may be performed by a calibration target similar to thecalibration target 600 except that the processor of the calibrationtarget may determine adjusted parameters for the ultrasonic transducers,and the transmitter does not output sensor data but instead outputs theadjusted parameters to the control unit 112.

In some implementations, care may be taken to avoid having the sensorsmodify coupling performance and skew measurements. Avoidance may includeusing two calibration targets, a first being a tuning target with adense array of sensors around important locations, and a second being aconfirmation target with inclusions and deeply embedded sensors that areable to measure effective performance of the system but not likely tocontaminate the result or provide information.

In some implementations, the process 900 may include using multipletargets with varying properties. For example, rigidly fixed calibrationtargets with many sensors may be used for initial calibration, followedby floating or buoyant calibration targets with limited sensor feedbackfor end-to-end validation and fine calibration. The process 900 mayoccur at regular intervals (e.g, at each start-up or hourly).

While the process 900 is described with respect to ultrasonic energy,the process 900 may similarly apply to other types of energy. Forexample, the process 900 may be used with lasers and laser sensorsinstead of ultrasonic transducers and ultrasonic sensors.

FIG. 10 is a flow diagram illustrating an example of a process 1000 formanufacturing a calibration target. For example, the process 1000 may beused to manufacture the calibration target 600.

The process 1000 includes obtaining a fish-shaped structure (1010). Forexample, a fish-shaped structure 610 may be 3D printed from a 3Dprinter. In another example, the fish-shaped structure 610 may beobtained from a commercial supplier of phantom fish.

The process 1000 includes placing sensors at different locations of thefish-shaped structure (1020). For example, a robot may automaticallyinsert the sensors 620 in or on the scale layer 618 of the fish-shapedstructure 610 at different locations of the fish-shaped structure 610.As discussed above, the different locations may be selected based onprioritizing locations where (i) sea lice may be located so energy maybe verified to be at least enough to remove the sea lice and (ii) fishare more sensitive so energy may be verified to be below unsafe levels.

The process 1000 includes installing a processor that receives sensorvalues from the sensors (1030). For example, a robot may automaticallyinsert the processor within the bulk mass 616 and wire the processor 630to each of the sensors 620.

The process 1000 includes installing a transmitter that outputs sensordata from the calibration target based on the sensor values (1040). Forexample, a robot may automatically insert the transmitter 640 andconnect the transmitter 640 to the processor 630 and the waterproof thinwire 632.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure. For example, various formsof the flows shown above may be used, with steps re-ordered, added, orremoved.

Embodiments of the invention and all of the functional operationsdescribed in this specification can be implemented in digital electroniccircuitry, or in computer software, firmware, or hardware, including thestructures disclosed in this specification and their structuralequivalents, or in combinations of one or more of them. Embodiments ofthe invention can be implemented as one or more computer programproducts, e.g., one or more modules of computer program instructionsencoded on a computer readable medium for execution by, or to controlthe operation of, data processing apparatus. The computer readablemedium can be a machine-readable storage device, a machine-readablestorage substrate, a memory device, a composition of matter affecting amachine-readable propagated signal, or a combination of one or more ofthem. The term “data processing apparatus” encompasses all apparatus,devices, and machines for processing data, including by way of example aprogrammable processor, a computer, or multiple processors or computers.The apparatus can include, in addition to hardware, code that creates anexecution environment for the computer program in question, e.g., codethat constitutes processor firmware, a protocol stack, a databasemanagement system, an operating system, or a combination of one or moreof them. A propagated signal is an artificially generated signal, e.g.,a machine-generated electrical, optical, or electromagnetic signal thatis generated to encode information for transmission to suitable receiverapparatus.

A computer program (also known as a program, software, softwareapplication, script, or code) can be written in any form of programminglanguage, including compiled or interpreted languages, and it can bedeployed in any form, including as a stand-alone program or as a module,component, subroutine, or other unit suitable for use in a computingenvironment. A computer program does not necessarily correspond to afile in a file system. A program can be stored in a portion of a filethat holds other programs or data (e.g., one or more scripts stored in amarkup language document), in a single file dedicated to the program inquestion, or in multiple coordinated files (e.g., files that store oneor more modules, sub programs, or portions of code). A computer programcan be deployed to be executed on one computer or on multiple computersthat are located at one site or distributed across multiple sites andinterconnected by a communication network.

The processes and logic flows described in this specification can beperformed by one or more programmable processors executing one or morecomputer programs to perform functions by operating on input data andgenerating output. The processes and logic flows can also be performedby, and apparatus can also be implemented as, special purpose logiccircuitry, e.g., an FPGA (field programmable gate array) or an ASIC(application specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read only memory ora random access memory or both. The essential elements of a computer area processor for performing instructions and one or more memory devicesfor storing instructions and data. Generally, a computer will alsoinclude, or be operatively coupled to receive data from or transfer datato, or both, one or more mass storage devices for storing data, e.g.,magnetic, magneto optical disks, or optical disks. However, a computerneed not have such devices. Moreover, a computer can be embedded inanother device, e.g., a tablet computer, a mobile telephone, a personaldigital assistant (PDA), a mobile audio player, a Global PositioningSystem (GPS) receiver, to name just a few. Computer readable mediasuitable for storing computer program instructions and data include allforms of non volatile memory, media and memory devices, including by wayof example semiconductor memory devices, e.g., EPROM, EEPROM, and flashmemory devices; magnetic disks, e.g., internal hard disks or removabledisks; magneto optical disks; and CD ROM and DVD-ROM disks. Theprocessor and the memory can be supplemented by, or incorporated in,special purpose logic circuitry.

To provide for interaction with a user, embodiments of the invention canbe implemented on a computer having a display device, e.g., a CRT(cathode ray tube) or LCD (liquid crystal display) monitor, fordisplaying information to the user and a keyboard and a pointing device,e.g., a mouse or a trackball, by which the user can provide input to thecomputer. Other kinds of devices can be used to provide for interactionwith a user as well; for example, feedback provided to the user can beany form of sensory feedback, e.g., visual feedback, auditory feedback,or tactile feedback; and input from the user can be received in anyform, including acoustic, speech, or tactile input.

Embodiments of the invention can be implemented in a computing systemthat includes a back end component, e.g., as a data server, or thatincludes a middleware component, e.g., an application server, or thatincludes a front end component, e.g., a client computer having agraphical user interface or a Web browser through which a user caninteract with an implementation of the invention, or any combination ofone or more such back end, middleware, or front end components. Thecomponents of the system can be interconnected by any form or medium ofdigital data communication, e.g., a communication network. Examples ofcommunication networks include a local area network (“LAN”) and a widearea network (“WAN”), e.g., the Internet.

The computing system can include clients and servers. A client andserver are generally remote from each other and typically interactthrough a communication network. The relationship of client and serverarises by virtue of computer programs running on the respectivecomputers and having a client-server relationship to each other.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of the invention or of what may beclaimed, but rather as descriptions of features specific to particularembodiments of the invention. Certain features that are described inthis specification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable subcombination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. In certain circumstances, multitasking and parallel processingmay be advantageous. Moreover, the separation of various systemcomponents in the embodiments described above should not be understoodas requiring such separation in all embodiments, and it should beunderstood that the described program components and systems cangenerally be integrated together in a single software product orpackaged into multiple software products.

Particular embodiments of the invention have been described. Otherembodiments are within the scope of the following claims. For example,the steps recited in the claims can be performed in a different orderand still achieve desirable results.

What is claimed is:
 1. A calibration target comprising: a fish-shapedstructure; sensors positioned at different locations of the fish-shapedstructure, wherein each of the sensors sense energy at a respectivelocation of the fish-shaped structure; a processor that receives sensorvalues from the sensors; and a transmitter that outputs sensor data fromthe calibration target based on the sensor values, wherein thefish-shaped structure includes: a bulk mass that mimics fish muscleresponse to the energy; a scale layer that mimics fish scale response tothe energy, wherein the scale layer is over the bulk mass; and a fishmucus layer that mimics fish mucus response to the energy, wherein thefish mucus layer is over the scale layer, and wherein the sensorsinclude a particular sensor inside a parasite target that mimicsparasite response in respect to the energy, wherein the parasite targetis positioned beneath the fish mucus layer and above the bulk mass. 2.The calibration target of claim 1, wherein the fish-shaped structureincludes a gill plate portion, a dorsal fin portion, and a caudal finportion, and wherein the sensors include a first sensor at the gillplate portion, a second sensor at the dorsal fin portion, and a thirdsensor at the caudal fin portion.
 3. (canceled)
 4. (canceled)
 5. Thecalibration target of claim 1, wherein the sensors comprise ultrasonicsensors that sense ultrasonic energy.
 6. The calibration target of claim5, wherein the sensor values indicate an amount of ultrasonic energysensed at the respective locations.
 7. The calibration target of claim1, wherein the sensors comprise at least one of: force sensors thatsense physical force; or photodiodes that sense light.
 8. Thecalibration target of claim 1, wherein the processor is amicrocontroller that is embedded within the fish-shaped structure,wherein the microcontroller is coupled to the sensors by electricallyconductive wires.
 9. The calibration target of claim 1, wherein thetransmitter outputs the sensor data over an electrically conductivewire.
 10. The calibration target of claim 1, wherein the transmitteroutputs the sensor data wirelessly.
 11. The calibration target of claim1, wherein the sensor data indicates the respective locations of thesensors positioned at the different locations of the fish-shapedstructure.
 12. The calibration target of claim 11, wherein thefish-shaped structure includes a non-transitory computer-readable mediumthat stores a configuration file that indicates the respective locationsof the sensors positioned at the different locations of the fish-shapedstructure.
 13. A computer-implemented method, comprising: obtaininginitial parameters for ultrasonic transducers around a calibrationtarget, wherein the calibration target includes: a fish-shapedstructure; sensors placed at different locations of the fish-shapedstructure, wherein each of the sensors sense energy at a respectivelocation of the fish-shaped structure; a processor that receives sensorvalues from the sensors; and a transmitter that outputs sensor data fromthe calibration target based on the sensor values; obtaining the sensordata from the calibration target; determining the respective locationsof the sensors; and determining adjusted parameters for the ultrasonictransducers around the calibration target based on the sensor data andthe respective locations of the sensors.
 14. The method of claim 13,wherein determining the respective locations of the sensors comprises:determining parts of the fish-shaped structure that each of the sensorsare located at.
 15. The method of claim 13, wherein determining therespective locations of the sensors comprises: determining a location ofthe calibration target within a sea lice treatment station.
 16. Themethod of claim 13, wherein determining a location of the calibrationtarget within a sea lice treatment station comprises: determining thelocation of the calibration target within the sea lice treatment stationwith a secondary localization system.
 17. The method of claim 13,wherein obtaining the sensor data from the calibration target comprises:determining a first portion of the sensor data from the calibrationtarget while the calibration target is at a first location within a sealice treatment station; and determining a second portion of the sensordata from the calibration target while the calibration target is at asecond, different location within the sea lice treatment station.
 18. Acalibration target obtained by a process comprising: obtaining afish-shaped structure; placing sensors at different locations of thefish-shaped structure, wherein each of the sensors sense energy at arespective location of the fish-shaped structure; installing a processorthat receives sensor values from the sensors; installing a transmitterthat outputs sensor data from the calibration target based on the sensorvalues; and coupling the processor with the sensors by electricallyconductive wires.
 19. The calibration target of claim 18, whereinobtaining the fish-shaped structure comprises: obtaining a bulk massthat mimics fish muscle properties in respect to the energy; forming,over the bulk mass, a scale layer that mimics fish scale properties inrespect to the energy; and forming, over the scale layer, a fish mucuslayer that mimics fish mucus properties in respect to the energy. 20.The calibration target of claim 19, wherein placing sensors at differentlocations of the fish-shaped structure comprises: embedding a particularsensor underneath the fish mucus layer and inside the scale layer. 21.(canceled)